中山大学匡代彬团队报道了具有蓝色热激活延迟荧光的高效X射线闪烁体碘化磷。相关研究成果2024年7月5日出版的《德国应用化学》。

有机闪烁体因其丰富的元素储量、简便的制备程序和丰富的结构而备受赞誉。

该文创新性地采用季鏻作为电子受体，二甲胺基和卤化物阴离子（I^-）作为电子供体，设计了一类具有热激活延迟荧光（TADF）的高效有机卤化鏻盐。所制备的丁基（2-[2-（二甲基氨基）苯基]苯基）二苯基碘化鏻（C4-I）表现出明亮的蓝色发光和100%的超高光致发光量子产率（PLQY）。在固态C4-I中，通过独特的n-π和阴离子-π堆叠实现了有效的电荷转移。

C4-I的光物理研究表明，I的引入导致了高的系统间穿过率（kISC）和反向系统间穿过速率（kRISC），抑制了本征的瞬发荧光，并在室温下实现了近纯的TADF发射。得益于I所赋予的大斯托克斯位移、高PLQY、有效的激子利用率和显著的X射线衰减能力，C4-I提供了80721个光子/MeV的卓越光产额和22.79 nGy·s^-1的低探测极限（LoD）。

该项工作将提供一个合理的设计概念，并为开发具有可调谐发射、强X射线衰减能力和优异闪烁体性能的高效有机闪烁体开辟一条有吸引力的道路。

附：英文原文

Title: Phosphonium Iodide Featuring Blue Thermally Activated Delayed Fluorescence for Highly Efficient X-ray Scintillator

Author: Jun-Hua Wei, Jian-Bin Luo, Zi-Lin He, Qing-Peng Peng, Jing-Hua Chen, Zhi-Zhong Zhang, Xiu-Xian Guo, Dai-Bin Kuang

Issue&Volume: 2024-07-05

Abstract: Organic scintillators are praised for their abundant element reserves, facile preparation procedures, and rich structures. Herein, a new family of highly efficient organic phosphonium halide salts with thermally activated delayed fluorescence (TADF) are designed by innovatively adopting quaternary phosphonium as the electron acceptor, while dimethylamine group and halide anions (I-) serve as the electron donor. The prepared butyl(2-[2-(dimethylamino)phenyl]phenyl)diphenylphosphonium iodide (C4-I) exhibits bright blue emission and an ultra-high photoluminescence quantum yield (PLQY) of 100%. Efficient charge transfer is realized through the unique n-π and anion-π stacking in solid-state C4-I. Photophysical studies of C4-I suggest that the incorporation of I accounts for high intersystem crossing rate (kISC) and reverse intersystem crossing rate (kRISC), suppressing the intrinsic prompt fluorescence and enabling near-pure TADF emission at room temperature. Benefitting from the large Stokes shift, high PLQY, efficient exciton utilization, and remarkable X-ray attenuation ability endowed by I, C4-I delivers an outstanding light yield of 80721 photons/MeV and a low limit of detection (LoD) of 22.79 nGy·s-1. This work would provide a rational design concept and open up an appealing road for developing efficient organic scintillators with tunable emission, strong X-ray attenuation ability, and excellent scintillator performance.

DOI: 10.1002/anie.202410514

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202410514